Connect with TRB

THE EMISSIONS AND FUEL ECONOMY OF A DETROIT DIESEL 6-71 ENGINE BURNING A 10-PERCENT WATER-IN-FUEL EMULSION

Initial efforts with water/fuel emulsions in diesel engines were directed toward the control of NOx. More recent studies emphasized the use of emulsions to improve fuel economy. It is believed that in a diesel engine combustion process, emulsified fuel droplets would undergo micro-explosions that would decrease the heterogeneity of the injector spray pattern and thus increase the efficiency and fuel economy. Although all data in the literature indicate that emulsions do lower the levels of NOx and smoke, carbon monoxide (CO) and hydrocarbons (HC) generally increase, depending on the amount of water in the emulsion, and the engine type, speed, and load. Reported fuel economy either decreases or increases, again, dependent on the water content, engine type and design, and engine speed and load. Other possible effects, such as increased fuel injector corrosion, water dilution of the lubricating oil, and the possibility of increased combustion chamber deposits have not been studied. The task reported here is a preliminary investigation of water/fuel emulsions in a GM6-71 engine. Surface active agents (surfactants), were used to produce the emulsions for this task. The purposes of this preliminary effort were to resolve the conflicting results in the literature, assess potential problem areas, and aid in formulating future efforts.